Steam-boiler furnace



(No Model.) 2 Sheets-Sheet 1.

0.. D. ORVIS. STEAM BOILER PURNAGE. No. 503,214. PatentedAug. 15, 1893.

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o. 1), 0mm STEAM BOILER PURNAGE. I 7 No. 503,214. 4 Patented Aug. 1 5?;1 893.

UNITED STATES PATENT OFFICE,

ORLANI) D. ORVIS, OF CHICAGO, ILLINOIS.

STEAM-BOILER FU RNAC E.

SPECIFICATION forming part of Letters Patent No. 503,214, dated August15, 1893. Ap lication filed October 31,1292. serial No. 50,478. (Nomodel.)

To aZZ whom it may concern.-

citizen of the United States, residing in the city of Chicago, county'of Cook, and State of Illinois, have invented certain new and usefulImprovements in Steam-Boiler Furnaces, of which the following is aspecification.

This invention relates generally to improvements in steam boiler andother furnaces in which a fire chamber is entirely within the confinesof a solid arch spanning a grate-bar surface, and whence the products ofcombustion must escape through its end, or else downward through thegrate bars, before theycan enter a combustion chamber either immediatelyabove or rearward of the fire chamber; but more specifically to thestructure shown, described and claimed in the pending joint application,Serial No. 429,735, filed by Orel D.

Orvis and myself April 19, 1892, in which,in a down draft furnace thereis a draft passage through which the down draft products of combustionare conducted to a combustion chamber over the fire chamber and at apoint forward of the rear end of said combustion chamber. I

The prime object of this invention is to successfully utilize to amaximum degree an arch-like fire chamber structure of a steam boiler orother furnace as a direct heating surface for boiler or other water, andat the same time promote the protection of that structure from thedestructive effects of the high degree of heat to which itis necessarilysubjected.

Afurther object is notonly to utilize an arch-like fire chamberstructure as a heating surface for boiler or other water, but in such amanner that the heat units, rising in a vertical line from the bed ofburning fuel with in the fire chamber, and at their highest temperature,shall impinge against the under wa ter heating surface of the arch andbe held in contact therewith the greatest possible time consistent withtheir successful after discharge into the furnace combustion chamber forfurther Work, and that the upper surface of the heating chamber of thearch shall receive the direct contact and effect of said heat unitsbefore they have ascended substantially above the bottom of saidcombustion chamber, or in contact with the crown sheets of aboilerorothersurface'to be heated, whereby the Water heating capacity of thesurfaces of an arch is promoted to a maximum degree, while at the sametime said surfaces and other surfaces beyond the arch are to acorresponding degree protected from the destructive effects of furnaceheat.

A further object of this invention is to substantially and materiallyincrease the water heating surface of a steam boiler furnace insuchamanner that the entire surface of the boiler within the furnace,and this increased heating surface, shall be subjected to substantiallyall of the heat units of a furnace under the most favorable conditionspossible for vaporizing water, and this without substantially increasingthe dimensions of any portion of said furnace orboiler, or diminishingany chamber or the grate surface thereof.

Other objects of my invention, more in detail, are the untilization ofthe arch or arches inclosing the fire chamber of a down-draft furnace asa direct heating surface for boiler or other water, and as a means forpromoting the circulation of water through a boiler and through a hollowgrate-bar surface, and by such an arrangement of parts that every atomof heat produced in the fire chamber of a down-draft furnace, when atits highest temperature, and temporarily confined, shall be di rectedinstraight and direct lines against and absorbed as fully as possible byan extended water heating surface in close proximity to the burningfuel, whereby Water is rapidly reduced to vapor and the temperature ofthese vapors raised to the utmost capacity possible by a unit of heat ofany given degree, and this without the employment of ahy degree oftemperature therein unduly promoting the destruction of the boilershell, while at the same time said arch or arches and grate-bar surfaceare effectively protected from destruction by furnace heat.

A further object is not only to convert the arch or arches of adown-draft. furnace intoa water heating surface and to employinconnection therewith a single or double hollow grate-bar surface,affording additional water surface, but to have such a connection ofthese hollow grate bars with each other and with the arch or arches thatthere shall bean open communication between all of these parts; that thegrate bars and arch or arches may be permanently connected and bodilyplaced in or removed from a furnace, and one or more grate bars removedor inserted conveniently, and without disturbing any other portions ofthe structure, whereby the necessity of putting together the arch andgrate bar surfaces within the furnace is avoided, and time iscorrespondingly saved in combining my invention with an ordinary steamboiler furnace already in use.

Further objects of my invention, hereinafter described and claimed, areattained bythe devices illustrated in the accompanying drawings, inwhich- Figured illustrates in detail a central longitudinal section of adown-draft steam boiler furnace embodying my invention; Fig. 2, atransverse section thereof on the line 2-2 of Fig. 1; Fig. 3, a frontelevation of the same with the furnace walls'removed; Fig. 4, anenlarged rear end elevation of one of the arches; Fig. 5, a transversesection on the line 55 of Fig. 6 of a down-draft steam boiler furnace,showing the embodiment of my invention in a single arch fire chamberstructure; and Fig. 6, a central longitudinal section of the same.

Similar letters of reference indicate the same parts in the severalfigures of the drawings.

A, A, indicate the side walls, and B the rear end wall of a steam boilerfurnace supporting a steam boiler O, of the ordinary construction, inthe usual manner, and provided with one or more furnace doors D, and ashpit doors E, of the usual construction and arrangement, the rear end ofthe ash pit being closed by a bridge wall F, the front side of which isstepped, as shown, and for the purpose indieated.

Arranged longitudinally of the chamber thus formed between the bridgewall and the front wall of the furnace, are arches G, G, which, asshown, may be set partially into the side walls of the furnace, but ifdesired may be set against said side walls, or at a point removedtherefrom, and supported at each end respectively by the front wall ofthe furnace and the bridge wall, but, in any event, are so arrangedrelative to each other that there is a passage a, at one or both sides,extending substantially their entire length. The forward end of thesearches is open and registers with the fire chamber doorway, and theirrear end closed by a head G which head or end and the body of the archconsist of an inner and outer shell providing between them a closedwater chamber 1), of considerable capacity, the walls of which arepreferably constructed of steel, but may be of any other suitablematerial adapted for a water tight chamber subject to furnace heat. Atthe forward end of the arch is a header 0, in open communication at bothends with the base of the water chamber of the arch and having also incommunication therewith grate bars d, the opposite ends of which areconnected and in open communication with the chamber of the head G asindicated in Fig. 1, which grate bars (I, in connection with the arch orarches G, G, constitute the fire chamber, H, of the furnace. Ifdesirable, for increasing the grate and water heating surface, thehollow grate bars may be staggered, that is to say, alternately arrangedin differing planes, and are preferably secured in con nection with theheader, 0, by screwing them into the wall thereof and to the end G bymeans of an ordinary elbow coupling, e, as shown in Fig. 1, which modeof connection of the grate bars with the arches provides for theconstruction of the fire chamber in its entirety before insertion into afurnace, and for the convenient bodily insertion and removal of one ormore grate bars from a furnace, and also when at any time desirable. Inother words, considerable saving of valuable time is eii'ected incombining my invention with an ordinary steam boiler furnace, by reasonof this construction providing for joiningbodily all of the parts ofafire chamber structure, and in this condition setting them into thefurnace, for any of the grate bars, though thus fitted and permanentlyjoined to the arch or arches before insertion into the furnace, may beremoved and inserted at any time thereafter without disturbing thearches, and also the entire fire chamber structure be removed for anypurpose whatever.

In a plane below the fire chamber are grate bars, d, and in the ash pitof the furnace,arranged substantially parallel with the grate barsurface cl, is a series of pipes, f, removably secured at their rearendsto a header, 9, by ordinary coupling, h, and at their forward ends arescrewed into a header 7c, the header g being connected with the gratebars (I by means of a pipe 1', and a T'coupling i, (see Fig. 1,) wherebythe rear ends of the pipes f, and the header g, may be suspended fromthe upper grate bar surface (1, but are perfectly supported by a ledgeof the bridge wall as indicated in Fig. 1, or may be suspended byprojecting the header g into the side walls of the furnace, orsupporting it upon suitable brackets secured thereto, as headers arecommonly supported in furnaces. The supply of Water to both the arch orarches, the grate bars and the water heating surface or pipes 70, may beseparately or conjointly from two sources, as, for instance, through apipe m, communicating with the boiler and with the headers c and 70, orby means of a pipe at, in communication with a water system or feedwater heater, and connected with both the header 0, and header is, bythe pipe or pipes m,or, if desired, water from the boiler may besupplied to the water chamber of the arch and the grate bars of the firechamber from the boiler, and the cold water be supplied to the pipes, f,in the ash pit through the pipe at. This latter mode is preferable,beeausea supply of water through the pipe n, is an additional supply forthe boiler, having its temperature raised before admission thereto, andby first passing through the pipes f, the header g, and thence into thegrate bars d, and water chamber of the arch, where it is combined withthe more highly heated water in said chambers, and discharged with theminto the boiler,

A continuous circulation of water through the arch chamber and the gratebar surface and pipe is, and a supply of said water to the boiler, areestablished by a pipe 0, connected with the water chamber 1), of thearch, preferably in a plane above the opening of the supply pipe ontherein, and, as shown, by inserting the pipe 0, into the top or crownof the arch, an ordinary elbow-joint 10-, being used for the purpose ofthis connection of the pipe 0 with the water chamber, 6, and providingfor the convenient connection and disconnection of the arch with saidexitpipeo. The exit or discharge pipe 0, while not so shown, maybeextended to the rear end of the boiler and connected vtherewith eitherin a plane with or above that of the orifice of the pipe m, whichextension of the pipe, through the combustion chamber of the furnace,correspondingly increases theextent of the water.

heating surface therein, but it would be no departure from my invention,to provide a pipe connection from the arch water chamber to any point ofthe boiler, though obviously, a greater length of circulation of thewater through the boiler, and an increase of heating surface areprovided by the end connection before described.

In Figs.5 and 6, myinvention is illustrated as embodied in'a down-draftfurnace, in which all of the products of combustion escape downwardlythrough the grate bars, and from the rear end of the arch. over thebridge wall, to the usual furnace combustion chamber rearward thereof,and hence rendering the space or chamber between the arch and the boilera dead-air space, correspondingly reducing the water heating surface ofthe boiler, and this by reason of there being no passage or passages up,through which the down-draft products can ascend to said chamber. Inthis connection it is proper to observe that it would be no departurefrom the spirit of my invention, as set forth herein, to embody it inany up-draft furnace wherein the grate surface is spanned by an archextending throughout its length, and the products of combustion from thefire chamber pass directly through the end of said arch to and over thebridge Wall.

7 Nor would it be a departure from my invenshown and described, nor toembody it in a furnace wherein is employed a baking, heating or otheroven instead of a steam boiler, for obviously the water heating capacityof the arch and the utilization of the products of combustion in thefire chamber for heating the water of said chamber and the protection ofthe arch by that water will remain the same in all of these differentstructures, wherein there is the same arrangement of arch, thoughobviously the heating capacity of the water chamber arch is materiallyand substantially increased in a down-draft furnace, when there is adirect up-draft passage at one side of and extending the length of thearch or arches thereof, by means of which a heretofore dead-air chamberabove said arch or arches is converted into a direct draft chamber, andby this means the outer water heating surface of the arch or arches issubjected to the heat of these products of combustion, as they are notin the, construction shown in Fig. 4, and in the open rear end arch ofthe direct upward draft furnace referred to,

The embodiment of o my invention in the side draft structure of adown-draft furnace illustrated herein in Figs. 1 to 4:, is a verysubstantial improvement in down-draft fur naces, as comparedwith thestructure shown in Figs. 5 and 6, and this not only because of thesubjection of, the upper and outer wate heating surfacesof the arch todirectdraft heat, but for the additional reason that a much moreeffective draft, and correspondingly rapid combustion, is secured, forthat by this exclusively end discharge in a down draft furnace practicedemonstrates, there to be a choking of the heat products in the passagebetween said end and the combustion chamber rearward of the bridge wall;whereas, in my particular structure,an extended llp-dlaftpassage at oneside of the arch receives the down-draft products as fast as they candescend through the grate bars, and as rapidly conducts them to thecombustion chamber or chambers of the furnace or boiler, as may be; andthis is true whether the combustion chamber extending the length of thearch is immediately over or in part or wholly at one side thereof, as Ihave discovered since filing the joint application aforesaid. For thesereasons the invention embraced by the arrangement of the arches shown inFigs. 1 and 2, is not to be limited specifically to a down-draftfurnace, wherein there is a draft passage through which the down-draftproducts of combustion are conducted to the combustion chamber directlyoverthe fire chamher, and at a point forward of the rear end of saidcombustion chamber, as claimed therein, but includes a down-draftfurnace, the grate bar surface of which is inclosed by an arch or archesso arranged as to provide a direct draft passage at one side of andextending the length of said arch or arches, whether or not said directdraft passage communicates with a chamber immediately over or in partare solid or provided with a water heating chamber partly or whollythroughout their surface.

In all downdraft furnaces, prior to the invention, of my jointapplication, the fire chamber grate bars must be so far apart in orderto have a sufficient draft for their practical operation that a largeamount of uneonsumed coal fuel drops through them, to save which, thecommon practice has been to have in a plane below the fire chamber gratebars, a supplemental grate surface with its bars closer together thanthe fire chamber grate bars, for catching and sustaining said unconsumedfuel until reduced to ashes. There are how ever, several unavoidable,objectionable results due to the use of a supplemental grate surfaceamong which may be mentioned the necessity of raking down two gratesurfaces for every fire chamber; the additional expense in first costand after repairs and renewals; and the occupancy of space more valuablesolely for water heating purposes. Furthermore, the application of theseprior own draft structures to ordinary furnaces ans dy in use and ofwhich there are thousands in basements and under sidewalks and elsewhereis impossible, wherein on account of drainage, the bottom of the ash pitcannot be lowered, as must be, in order to provide between the firechamber grate surface and the supplemental grate surface a chamber of acapacity suificient for the commingling and expansion of the products ofcombustion from both grate surfaces, to a degree necessary for thesuccessful utilization of those products, and as a condition precedentto their successf ul discharge to and over the bridge wall, even underthe most favorable conditions for a furnace draft. At best however, theconsumption of fuel on a supplemental grate surface requires an airsupply upwardly therethrough from the ash pit, which supply unavoidablycauses a draft opposing and consequently retarding a downdraft of theproducts of combustion in the fire chamber to a degree practicallyrendering null any advantages accruing to the saving of fuel by means ofthe supplemental grate surface. Not only does this updraft oppose thedescent of the products of combustion through the fire chamber gratesurface but so does the rising of the products of combustion by theirnatural tendency from the supplemental grate surface, and when, to thesecombined forces, is added in any prior down-draft structures, thefurther requirement that a very large portion of the products ofcombustion must traverse the length or a substantial portion of theintermediate chamber horizontally before the possibility of their escapeto and over the bridge wall, it is obvious, that at best, the employmentof a supplemental grate surface in these prior structures or in any downdraft structure, is a serious obstruction to this successful operation.

Now my invention may be applied to any ordinary furnace already in usewithout increasing or diminishing the depth of the ash pit or theoriginal distance between the bottom of the ash pit and the fire chambergrate surface, while at the same time, the downdraft of the furnace andthe rapid and complete combustion of fuel on the grate surface of thefire chamber and without any waste of fuel, are promoted to asubstantial degree as compared with any of the prior downdraftstructures, and all this by reason of the fact, that there are no aircurrents or draft opposing the descent of the downdraft products, andthat immediately they discharge downwardly through the grate bars theyare free to escape laterally from beneath them along the entire lengthof the fire chamber and in the most direct path therefrom, and to riseby their natural tendency or gravitation into an enlarged chamber inwhich they are free to fully expand and discharge thence to and over thebridge wall without crowding or choking at any point, while at the sametime, their onward movement is accelerated by an unobstructed andperfectly free combustion-chamber draft. In other words, by my inventionthe combustion of fuel in the fire chamber of a down draft furnace, therapidity of its combustion, the discharge of the products of combustiontherefrom and through the entire length of the furnace and over thesurfaces therein to be heated, are promoted to a maximum degree and thiswithout any waste of fuel, and by devices requiring no obj ectionablechanges in an ordinary furnace to incorporate them, while, at the sametime, as shown by the pipes 7r, the chamber below the fire chamber gratesurface is successfully utilized for increasing the water heatingsurface of a furnace, and this without any obstruction to the draft ofthe furnace or objectionable obstruction to the ash pit.

In the operation of my device, with a bed of burning fuel on both of mygrate bar surfaces, and a circulation of water from any source throughthe arch or arches and these grate bar surfaces, to any supply, it isapparent that the inner water heating surface of the arch structure willbe subject in allot the arch structures I describe to products ofcombustion rising from and confined between the surface of the fuel andsaid inner water heating surface, and that said products of combustion,after substantial absorption by this heating surface, will pass directlyfrom the fire chamber to the combustion chamber Very little reduced intemperature, and in downdraft furnaces of this character, not reduced atall in temperature, but in the highest degree possible, by reason oftheir after passage through the body of burning fuel. In myspecia-lstructure, however, and by reason of the extended up-draft side passage,the heat units are utilized with substantially better effect upon thisinner water heating surface of the arch than in any of theotherstructures herein shown and described, and for the reason that theheat units, coming in contact with the arch, ascend thereto and descendtherefrom on practically direct lines, at which they best impart theirheat to a contacting surface; and furthermore, because by this ascendingand descending in the fire chamber above the burning fuel, their time ofconfinement therein and their contact with the water heating surface aresubstantially prolonged; Whereas, in an up-draft furnace, and also in adown-draft furnace having exclusively an end discharge, the heat unitsare constantly movlng in a horizontal direction against this innersurface. In the mean time the products of combustion from the gratebars, after descending therethrough upon the pipes f, raise thetemperature of the water therein, thus making said pipes a desirableauxiliary water heating surface. As the temperature of the water israised both in the arch water heating chamber, the grate bars and thesepipes, it rises and discharges through the pipe 0, the circulation ofthe water to this end being substantially promoted by means of theheader, and also by the connection of these grate bars with the Waterchamber 1), of the arch. When this arch and grate bar structure areemployed in connection with a steam boiler furnace, as, for example, bythe pipes on and 0, as before described, water at quite a hightemperature will be supplied to the boiler in starting the furnace, andthis is a considerable time before the heat of the furnace imparted tothe crown sheets of the boiler can possibly raise the temperature of thewater therein. In

view of this operation, the arch water chamber is not only an extendedwater heating surface, auxiliary to the boiler when the furnace is infull operation, but is an important factor in the initial heating of theboiler water, and also in raising the temperature of the boiler waterquickly when already heated.

The capacity for heating boiler water and the extent of the heatingsurface of the arch chamber may be appreciated when it is borne in mindthat by the use of these archesin the usual fire chamber of a steamboiler, the heating surfaces are increased two hundred and fifty squarefeet, and that as five square feet of these highly heated water surfacesare equal to one horse power, the addition of two hundred and fiftysquare feet of heating surfaces adds fully fifty horse power to theboiler.

The importance of my invention in connection with a steam boiler furnaceis not confined to the fact of the extended water heating surface itprovides, but more largely to the manner of utilizing that surface so asto subject it to heat of the degree, and in the manner alreadydescribed.

In conclusion it is proper to observe, that an important advantage isgained by having an updraft passage along the side of the arches, inthat the length of the grate surface may be extended without limit and acorrespondingly larger area of grate surface be operated without anyreduction or retardation of the draft in any portion of the furnace, andas cannot be when an exclusively end up draft passage is employed,because, even with a length of grate surface very short as compared withthe usual length of mine, to say nothing of the extension permissible bymy side up draft passage, the objectionable crowding and choking of theproducts of combustion and retarding of draft,before stated, areYcorrespondingly increased as the length of grate surface is increased,and said products are compelled to travel a greater distance beforereaching the updraft passage.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is

1. The combination in a down-draft furnace,

'of grate bars, a fire chamber, an arch inclosing said fire chamber, adirect updraft passage at the side .of said arch, and a water heatingchamber internally of the arch, substantially as described.

2. In a down draft furnace the combination of the grate bars, an archspanning the same, a direct updraft passage at one side of and extendingthe length of said arch, and a water heating chamber internally of andextending throughout said arch, substantially as described.

3. In a down draft furnace, the combination with the grate bars, of anarch or arches inclosing the same, and arranged to provide a directupdraft passage at one side of and extending substantially the length ofsaid arch or arches, substantially as set forth.

4. In a down draft furnace, the combination with an arch or archesspanning the grate bar surface and inclosing the fire chamber, whichsaid arches are so arranged as to provide a direct draft passage at oneside of and extending substantially the length of said arch or arches,and awater chamber inclosed by the opposing surfaces and extendingsubstantially throughout said arch or arches, substantially as setforth.

5. In a steam boiler furnace, the combination with the grate bars, of aclosed arch or arches spanning but notsurrounding thegrate bars andinclosing the fire chamber, a water chamber forming a closed archinternally of said arch or arches, and pipe connections between saidchamber and the boiler whereby a continuous circulation of water fromand through the boiler and said arch or arches and the grate bars, ismaintained, substantially as and for the purpose described.

6. In a furnace, the combination with hollow grate bars, of a closedarch spanning but not surrounding the grate bars, and pro: videdthroughout its length with an internal water chamber forming a closedarch connected with said grate bar surface, and also with a suitablesource and supply whereby a continuous circulation of water ismaintained through the hollow grate bars and arch water chambersubstantially as and for the purpose described.

7. In a down draft steam boiler furnace, the combination of hollow gratebars, an arch or arches spanning the same, inclosing the fire chamberand arranged to provide a direct draft passage at one side of andextending the tained, and the initial and subsequent heatlength of saidarch or arches, a supply and ing of the boiler water is promoted,substan- IO discharge pipe connection between said arch tially as setforth. or arches and the boiler, and a water connec- 5 tion between saidarch or arches and the grate ORLAND ORVIS' bar surface or surfacesthereof whereby a 0011- Witnesses: tinuous circulation of waterin theboiler and R. G. OMOHUNDRO, in said arch or arches and grate barsismaiu- F. A. HOPKINS.

